1. Field of the Invention
This invention relates to door latches. In one of its aspects, the invention relates to a door latch for a roll up door. In another of its aspects, the invention relates to a roll up door with a latch. In another of its aspects, the invention relates to a door latch assembly with a closed keeper that is moved into a locking position by the movement of a handle into a closed position. In another of it aspects, the invention relates to a door latch assembly with a closed keeper that is rotatably mounted to a plate for movement between fixed stops.
2. Description of the Related Art
U.S. Pat. No. 4,014,572 to Binns discloses a door latch assembly comprising a latch bolt, a closed keeper, and a bolt catch, all pivotally mounted to a support plate. The closed keeper is weighted so that a finger normally swings against a lug to maintain the keeper in the position illustrated in a closed position absence any force on it. The degree of rotation is limited by a pin on the keeper that fits within a slot on the support plate. The bolt catch is also weighted so that it is maintained in a ready position as well. The bolt catch further has a projection that catches a projection on the latch bolt to keep the bolt latch in the open position. The support plate is mounted to the door to thereby mount the entire latch assembly to the door. If the closed keeper is stuck in the unlatched position when the latch bolt is moved to the closed position, the closed keeper may not maintain the latch bolt in the closed position. Further there is no mechanism to lock the latch bolt in the closed position.
A currently available door latch assembly comprises a handle and hook pivotally mounted to a support plate, a closed keeper and an opened keeper. The closed keeper is pivotally mounted to the door and is weighted to retain the handle in a closed position. The handle also has at one end a transverse locking flange with an opening that registers with an opening in the closed keeper so that a padlock can secure the latch in the locked position. The closed keeper rotates about an axis above the axis of rotation of the handle and thus relies on gravity to position the closed keeper in the closed position. There is not positive or automatic movement of the closed keeper from the open to the closed position in the event that the closed keeper is stuck in the open position.